What is Groundwater Hydrology?

Dee Saale
Dee Saale
Dee Saale
Dee Saale
Scientist with beakers
Scientist with beakers

Groundwater hydrology helps many groups of people – from farmers to rural homeowners to industrial water supply leaders to well drillers – learn about the development, occurrence, and conservation of groundwater. Forty percent of the water that is used in our homes, businesses, and farms comes from groundwater, which is one of the world's most important resources. If you were to add the water that is used as a coolant in electric power plants and hydropower facilities, that percentage would be much higher.

Across the globe, water is naturally part of the hydrologic cycle in all of its forms, such as the atmosphere, surface water, oceans, and groundwater. The water on the Earth moves in a continuous cycle and has been in balance for millions of years. Conservation efforts are important, as water can be removed from the cycle by chemical and biological reactions, creating an imbalance in the hydrologic cycle in the future.

In order to fully understand groundwater hydrology, it is first important to understand what constitutes groundwater. It is the water that fills the fractures, pivots, and pores in the ground. It is often compared to milk filling the empty spaces in a piece of shredded wheat cereal, as it sits in the cereal bowl.

The surface of the groundwater, called the water table, must also be understood when studying groundwater hydrology. It can be close to the surface of the ground or hundreds of feet below the surface. In between the surface of the land and the water table is a region called the unsaturated zone. This is where the moisture moves towards the water table to replenish the groundwater.

There are geologic formations that contain large amounts of groundwater, called aquifers. The groundwater can be pumped from an aquifer for household, municipal, or farming uses. Groundwater always moves from areas of higher elevation to areas of lower elevation and from places of greater pressure to places where the presser is lower. Usually, this movement is painstakingly slow; however, many scientists are interested in this movement, also known as groundwater hydraulics.

While there are many jobs available for people interested in careers relating to groundwater hydrology, there are researchers who fear that there are not enough people interested in such a focused field of study. In fact, some reports that show that it has been difficult to fill entry-level positions in groundwater hydrology. Consequently, the imagination and interest of younger students must be sparked in the early years of school.

Dee Saale
Dee Saale

Dee is a freelance writer based in Colorado. She has a B.A. in English Literature, as well as a law degree. Dee is especially interested in topics relating to medicine, legal issues, and home improvement, which are her specialty when contributing to .

Dee Saale
Dee Saale

Dee is a freelance writer based in Colorado. She has a B.A. in English Literature, as well as a law degree. Dee is especially interested in topics relating to medicine, legal issues, and home improvement, which are her specialty when contributing to .

Discussion Comments


@GiraffeEars- Your hometown uses an interesting system to manage groundwater resources. I am from Honolulu, and I know one of the big constraints to growth in the city is access to fresh water. The water table on the island is not large enough to support the population, so there are problems with brackish water replenishing the groundwater reserves.

The city and the state will need to come up with ingenious ideas to facilitate future growth in the state. Most people think that Hawaii is a state filled with water, but the reality is that the islands are so new in geologic terms that they have very little groundwater reserves. On a number of the islands, people rely heavily on rainwater catchment cisterns to take advantage of the less reliable surface water that falls on the island.

This is one of the big practical problems in groundwater hydrology that my state deals with every day. Maybe the state could learn something from your city so that they can geoengineer a solution to water waste. A more robust and cyclical system of water management would be much better than the linear system that is implemented today.


@valleyfiah- I am from Fresno California and I am studying the dynamic between surface and groundwater hydrology in one of my classes. I actually used the city of Fresno as a case study because of their groundwater recharge program.

California gets a lot of surface water from multiple sources, but there is an overall water problem in the state. To improve water security, the city of Fresno coordinated a recharge program between a couple of the city's agencies. The program actually stores excess water in groundwater aquifers, and filters runoff into the same reservoirs through percolation. The city has a neat diagram on their website showing a rudimentary example of the process.

The cities of Clovis and Fresno siphon a portion of their water rights from the Kings and Joaquin rivers into reservoirs, where the water slowly percolates through pores in the bedrock to replenish groundwater. When big storms roll through the valley, the runoff is fed into the same system, allowing the runoff to filter into the aquifer as well. The purpose is to mitigate flooding by providing a path for potential runoff while alternately replenishing the regions drinking water supply. The recharge system is a low energy process that has helped to stabilize water resources in the area.


What factors play into groundwater recharge rates and how long does it take for groundwater to recharge? I have to write a report for school on groundwater recharge related to flood control and drinking water, and I do not know enough about groundwater recharge rates to understand how this has an impact.

I have read about cities using groundwater recharge projects to prevent flooding and to recycle runoff into the groundwater, but I do not understand the basics of this. I would appreciate any feedback on how these programs work and if they are really worth the costs. Does anyone know of any programs like these that I could use as a case study?


@Fiorite- Glasshouse is right. Think of the importance of environmental hydrology this way, the famine sweeping eastern Africa is due to crop failure from poor management of water resources. The recent splitting of Sudan into an Arab and Afrikaan state is the result of underlying cultural tensions brought on by drought and desertification. Relationships between Israel and surrounding Arab nations are strained by water scarcity. India and China have political tension due to international water rights.

Even in the United States, water rights are a big issue. Some areas are experiencing record drought (never mind the fact that these states are rich with resources like oil and gas that require large amounts of water to extract). The water rights to the Colorado River is shared between a number of large states and Mexico, and there is more claim to the water than there is actual water. The point being these problems are real, and they constrain growth in all sectors of the economy, environment, and political spheres.


@fiorite- Ground and surface water hydrology are probably some of the most important scientific fields worldwide. Not to knock what other scientists are researching, but the truth is the world is in the middle of a silent water crisis. Water is one of the last resources to be completely commoditized, but it is vitally important to every nation on the planet. Energy receives big press because of the relationship it has to big business, war, and economic growth, but water is even more vital than electricity or liquid fuels.

A lack of water resources can lead to wars, social collapse, and massive famine. I read in a UN report that somewhere around a third of the world's population does not have access to clean water. Making the issue of water resources more complicating is the fact that water resources, whether ground or surface, do not conform to state or national borders. Those that can help create a scientific understanding of how the hydrologic cycle works are crucial to policy development at every level.


Why are there so many positions open in the field of groundwater hydrology? I would not think that it would be such a high-demand field. How would someone get into this field, and how much does a hydrologist earn? Jobs are scarce at the moment, so the fact that there is a shortage of hydrologists surprises me.

Until reading this article, I had never heard of ground water hydrology. How important is hydrology research compared to other areas of scientific research like energy, medical, and information technology research?

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